Conventional chemical treatment of moving water systems such as cooling towers necessitates the use of hazardous materials that are continuously added the cooling tower water (CTW) through a drip system to prevent scale and microorganism build up in the HVAC equipment, pipes, and manifolds.
Scales are formed in HVAC equipment such as heat exchangers, condensers, evaporators, and cooling towers when hard water is heated or cooled. In cooling towers, even if the water is soft, the water quickly becomes hard due to evaporation. One of the most common types of scale is calcium carbonate, CaCO3, which forms from calcium and bicarbonate ions present in the water. The precipitation of these ions occurs due to their having less solubility in hot water, thereby causing hard scale formation on heat transfer surfaces (shown schematically in FIG. 1), reducing their efficiency.
Generally, scales are removed using acid chemicals, which procedure shortens the life of the equipment. In addition, chemicals in the concentrated form are often acute toxins, and their use is undesirable. Further, unless chemicals are added at the right time and rate, the use of chemicals to remove scale can be ineffective. Also, if improperly added to a system, chemicals may cause severe operational problems.
Alternative methods such as the use of mechanical mixing, vortex flow devices, and ultrasound have been proposed and are being used as alternative techniques to the use of chemicals. Unfortunately, these methods are mostly expensive and require heavy maintenance for proper operation.
As noted above, chemical treatment is also used to kill or prevent microorganism growth, particularly with regard to various types of bacteria that contaminate water systems. However, as with the chemical treatment for scale formation, the use of chemicals to kill, treat, or prevent biofilm and microorganism growth in water systems is costly, requires maintenance, and presents safety issues.
While pulsed power water treatment systems have been described for use in treating scale and/or biofilm growth, these systems can be cumbersome to implement into existing water treatment systems, ineffective in treating both scale and biofilm, and/or require high voltage.
The present invention is directed to addressing these and other deficiencies in the art.